Non-Communicable Diseases Watch Volume 5 Number 11 November 2012

Transcription

1 Non-Communicable Diseases Watch Volume 5 Number 11 November 2012 Health Tips To get the most benefit and enjoyment out of cycling, safety is the key. Most cycling injuries can be prevented with good cycling skills and manners and constant vigilance while cycling. Safe Cycling Cycling is an affordable, convenient and achievable form of physical activity for people of all ages and with different fitness levels. As an aerobic activity at the recreational level, regularly cycling can offer a number of health-enhancing effects. 1 Although cycling is a healthy and low-impact activity, it is not without risk of injury if safety precautions are not taken. Do you know that Bicycles were introduced in the 19 th century. Nowadays, the number of bicycles is about 1 billion worldwide, twice as many as motor vehicles. 2 In this Issue Page Safe Cycling. 1 News Bites.. 7 Data Brief.. 8 Health Benefits of Cycling Along with a balanced diet, cycling is one of the best ways to control or lose weight; it raises metabolic rate, builds muscle and burns body fat. At a typical commuting intensity, cycling (which has an intensity of about 6-8 metabolic equivalents [MET]) can burn more calories and yield greater health benefits than walking (at about MET). 3 For a 70 kg adult, cycling for an hour can burn approximately kilocalories. This publication is produced by the Surveillance and Epidemiology Branch, Centre for Health Protection of the Department of Health 18/F Wu Chung House 213 Queen s Road East Wan Chai, Hong Kong All rights reserved Many scientific studies have demonstrated the health benefits of cycling. In a systematic review released in 2011, all but two of the 16 cycling-specific studies included showed a positive relationship between cycling and health benefits among different age groups. 4 For children and adolescents, cross sectional and longitudinal studies showed that those who cycled to school had higher levels of cardiovascular and muscular endurance than those who walked or travelled by motorised transport. For working-age adults, interventional studies indicated consistent improvements in cardiovascular fitness and some improvements in cardiovascular risk factors from commuter cycling. As to the middle-aged and elders, prospective observational studies demonstrated an inverse relationship between commuter cycling and all-cause mortality, cancer mortality and morbidity. Some studies also showed that the more cycling the healthier for both sexes. For example, a study on Chinese adults aged reported that the risk of colon cancer in men who cycled minutes, 61 to 120 minutes, and more than 120 minutes a day was estimated to be 19%, 48% and 59%

2 lower than that in men who cycled less than 30 minutes a day respectively. The corresponding decrease in risk for women was 24%, 46% and 56%. 5 Another study on cycling for transport and mortality among Chinese women in Shanghai found that women who reported cycling and 3.5 or more MET-hours per day were at 21% and 34% reduced risk of all-cause mortality relative to those women who reported no cycling. 6 In addition to physical benefits, cycling is good for mental well-being too. As an aerobic exercise, cycling can stimulate the release of endorphins and serotonins, two brain feel good chemicals which can produce feelings of pleasure, reduce anxiety and wash away bad moods. A study on young healthy adults showed that 20-minute sessions of cycle ergometer exercise were effective in reducing state anxiety, regardless of whether the subjects cycled at low intensity (at 40% of maximum oxygen consumption [VO 2max ]) or high intensity (at 70% VO 2max ). 7 An intervention study on patients with depressive and anxiety disorders also reported significantly decreased state anxiety and negative affect after 20 minutes of cycling. 8 Injuries from Cycling As with all forms of physical activities, overuse injuries are common among cyclists. Cyclists are also susceptible to traumatic injuries, the severity of which can range from minor abrasions, lacerations and bruises of the skin, to fractures and joint dislocations or even fatal head trauma. Overuse injuries Most overuse injuries caused by cycling occur due to poor bike fit, improper riding techniques or overdoing. For instance, a seat positioned too far from the handlebars can cause pain in the neck and lower back, whereas a seat too close to the handlebars may lead to strain on both arms and back. Improper wrist positioning with too much pressure on the handlebars may cause compression neuropathies in the hands. An ill-fitting saddle can cause perineal compression and symptoms like genital numbness and erectile dysfunction in men. Repetitive bending and straightening of the hips and knees at too much pedal resistance during cycling can result in overuse injuries to those joints and surrounding soft tissues. An epidemiological analysis of overuse injuries among 518 recreational cyclists overseas showed that 85% of the cyclists reported one or more overuse injury/complaints. The most common anatomical sites reported were the neck (48.8%), followed by the knees (41.7%), groin/buttocks (36.1%), hands (31.1%), and back (30.3%). 9 Another study on 109 professional road cyclists found that low back pain and anterior knee pain were the most prevalent overuse injuries, with an annual prevalence of 58% and 36% respectively. 10 While one literature review of 62 articles on bicycling-related urogenital symptoms found that genital numbness was reported in 50% - 91% of all cyclists 11, another review of 35 studies on bicycle riding and erectile dysfunction showed that the prevalence of moderate to severe erectile dysfunction in bicyclists was 4.2%. 12 Traumatic injuries As for the disease burden due to traumatic injuries associated with cycling, in the U.S. alone, bicyclerelated injuries account for approximately 900 deaths, hospital admissions, emergency department visits and more than 1.2 million physician contacts per year. 13 Among children and adolescents aged 19 or below, cycling was one of the most common sports and recreational activities associated with emergency treatment for nonfatal Page 2

3 traumatic brain injuries (TBI). Between , a study showed that 8.1% of all emergency department visits for cycling injuries were TBIs. 14 Cyclists are among the most vulnerable road users because they are unprotected in traffic compared to other motor vehicle occupants. In a collision with a motor vehicle, they are almost always the weakest party and are more likely to sustain serious injuries or death. In Australia, hospitalisation data showed that the number of pedal cyclists injured with high threat to life due to a road traffic crash increased from 523 (or a rate of 2.7 per population) in 2000/2001 to 917 (or a rate of 4.3 per population) in 2007/ In Great Britain, the number of pedal cyclists seriously injured or killed in road accidents has gone up 24.5%, from in 2007 to in 2011; the total reported casualties among pedal cyclists have gone up 18.6%, from to in the same period. 16 The most common vehicle involved in collisions with cyclists was a car or taxi. In a serious injury involving heavy goods vehicles, buses and coaches, passing too close to the cyclist was judged to be a contributory factor in a quarter of the accidents. 17 The proportion of people died in road traffic injuries as cyclists varies between countries and regions, depending on the popularity of cycling as a form of commuting, degree of motorisation, design of road traffic system, land use policy, and legislative or related measures. In 2006/2007, the proportion varied from 2% - 3% in the U.S., Canada, Australia and New Zealand to 9% - 13% in China, Singapore and Japan. In the Netherlands, where there is a high cycling rate, cyclist deaths accounted for 24% of all road fatalities. 18 Other health risks Apart from injuries, there are concerns that cycle commuters in high-traffic areas are exposed to components of car exhaust fumes, including elemental carbon, ultrafine particles and soot, and that such fume components can contribute to heart and respiratory illness. A study on 42 healthy urban cyclists revealed that short-term exposure to trafficrelated air pollution might contribute to acute changes in heart rate variability in the hours immediately after cycling. 19 Local Situation In Hong Kong, although cycling is not the primary means of commuting, it is a popular activity for recreational and fitness purposes. 20 Cycling crashes and injuries are thus not uncommon. The Road Traffic Accident Statistics of the Transport Department showed that the annual number of cyclists involved in reported road accidents in Hong Kong has risen from in 2001 to in 2010, representing an increase of 28.6%. 21 Over the same period, among the pedal cyclists injured in traffic accidents, there were a total of 93 registered deaths, giving an average of about 9 cyclist deaths per year. Deaths in males outnumbered those in females, with an overall male to female ratio of about 4.5 to 1 (Table 1), and 72.0% of fatalities were among people aged 45 and above (Table 2). Overall, 63.4% of cyclist fatalities resulted from a collision with a car, a pick-up truck or a van, and 14.0% from a collision with a heavy transport vehicle or a bus. In 2010, cyclist deaths accounted for 8.2% of all road traffic fatalities. 22 As for the types of cycling injuries and the prevalence of helmet use in Hong Kong, an earlier local study on 698 bicycle-related injuries presenting to the emergency department of the Prince of Wales Hospital in 2006 provided some insights. Among the injuries, other than minor external wounds (including abrasions, lacerations and contusions), limb injuries were the most common (20.2%), followed by head injury (9.6%). Page 3

4 Table 1: Number (Rate*) of registered deaths due to pedal cyclist injured in traffic accident by sex, Year Male Female Total (0.1) 0 (0.0) 3 (<0.05) (0.4) 1 (<0.05) 13 (0.2) (0.2) 3 (0.1) 11 (0.2) (0.3) 2 (0.1) 12 (0.2) (0.1) 1 (<0.05) 5 (0.1) (0.2) 2 (0.1) 9 (0.1) (0.2) 3 (0.1) 11 (0.2) (0.3) 1 (<0.05) 10 (0.1) (0.2) 2 (0.1) 9 (0.1) (0.2) 2 (0.1) 10 (0.1) Total Note: *Rate per population of respective sex and year. Sources: Department of Health and Census and Statistics Department. Compared to the children aged 15 and below, those aged above 15 were 9.3 times more likely to be involved in a crash with a motor vehicle and sustain more serious injuries. More importantly, only 3 out of the 698 cyclists wore a helmet at the time of injury, giving an extremely low prevalence of helmet use at 0.4%. 23 Table 2: Number (Rate*) of registered deaths due to pedal cyclist injured in traffic accident by age group, Year 14 years years 60 years Total and below years years and above (0.0) 1 (0.1) 0 (0.0) 1 (0.1) 1 (0.1) 3 (<0.05) (0.2) 0 (0.0) 3 (0.2) 3 (0.2) 5 (0.5) 13 (0.2) (0.0) 0 (0.0) 1 (0.1) 9 (0.6) 1 (0.1) 11 (0.2) (0.0) 2 (0.1) 1 (0.1) 6 (0.4) 3 (0.3) 12 (0.2) (0.1) 1 (0.1) 1 (0.1) 0 (0.0) 2 (0.2) 5 (0.1) (0.0) 1 (0.1) 1 (0.1) 3 (0.2) 4 (0.4) 9 (0.1) (0.3) 4 (0.3) 0 (0.0) 3 (0.2) 1 (0.1) 11 (0.2) (0.1) 0 (0.0) 2 (0.1) 3 (0.2) 4 (0.3) 10 (0.1) (0.0) 1 (0.1) 0 (0.0) 3 (0.2) 5 (0.4) 9 (0.1) (0.0) 0 (0.0) 0 (0.0) 2 (0.1) 8 (0.6) 10 (0.1) Total Note: *Rate per population of respective age group and year. Sources: Department of Health and Census and Statistics Department. Page 4

5 Cycling Safety and Prevention of Injuries Cycling is a healthy and relatively safe activity, and the risks of cycling are low in general. While cycling injuries can be attributed to defective bike component, adverse weather conditions or some road factors such as potholes or objects on the road 24, cyclist s behavior also make a significant contribution. If fact, the major cyclist contributory factors in traffic accidents include careless cycling, losing control, riding inattentively, disobeying traffic signal, and starting negligently. 25 To get the most benefit and enjoyment out of cycling, safety is the key. Most cycling injuries can be prevented with good cycling skills and manners and constant vigilance while cycling. Here are some safe cycling rules, riding tactics and general health tips for cyclists to observe: Preparation and safety checks before starting > Choose a bike that fits your size; you should be able to touch the ground with tiptoes when sitting on the bike seat. A bike that is too big or too small can be dangerous and hard to control. Check and make sure the bike is in good condition, including the brakes, tyres, lights/reflectors, chain and horn/bell. > Wear a properly fitted helmet that meets the international standards. Research showed that wearing a helmet could reduce the risk of head or brain injuries by approximately two-thirds or more, regardless of whether the crash involved a motor vehicle. 26 Wear protective pads at the elbows and knees can reduce the severity of injury to your limbs in case you fall from your bike; wear cycling gloves to prevent hand numbness and pain that can occur on longer rides or off-road biking. > Dress appropriately. Wear bright or light-coloured clothing during the day and reflective or fluorescent clothing at night or under poor visibility. Make sure your pants are not so loose or so long that they can get caught up in the chain while you are cycling. Wear shoes that are enclosed and appropriate (e.g. stiff sole shoes can distribute pressure evenly over the pedal and reduce foot pain), and make sure that shoelaces are not loose or lengthy that they can get caught up in the chain. Do not wear sandals, flip-flops or go barefoot. > Get familiar with the cycling traffic rules and signs. Equip yourself with some emergency handling skills, such as dodging obstacles, quick turns and safe braking. For example, braking under normal circumstances can be performed by applying the rear brake before the front brake. Use the rear brake for smooth gradual slowing down and only brake when the front wheel is straight. When cycling on the road > Always use a cycling track if it is available. Where possible, select a cycling route that is away from traffic. > Obey all traffic rules, including traffic light signals, traffic signs and road markings. Ride at a safe speed. In crowded places, slow down or even dismount and wheel your bicycle. When using the pedestrian crossing, dismount and push your bicycle across. Yield to pedestrians at all times. > Keep left and cycle along the direction of traffic stream. Do not weave in and out of traffic. Ride in a single file when travelling in groups, except when overtaking. > Maintain a safe distance from the bicycle or vehicle ahead of you. Leave extra room riding near buses, trucks and parked cars. Avoid riding between two lanes of moving vehicles. > When negotiating turns or intersections, signal well in advance the direction you wish to go. Perform a shoulder check every time you want to change directions. Make eye contact with other road users before making your move. Page 5

6 > Watch out for obstacles on the road and surface hazards, such as raised surfaces, potholes, sewer grates, loose gravel, rocks, puddles of water or sharp objects. > Be visible and be heard on the roads. Switch on the front and rear lights when riding in the dark or at times of poor visibility. Use a bell or horn if indicated. > Do not carry passengers, and things that block your vision or upset your balance. Do not hold onto other vehicles. Other general health and safety tips > Never use handheld mobile phone or do any other activities that will distract your attention while cycling. Do not wear headphones as that will compromise your awareness of what is going on around you. > Cover exposed skin with sunscreen on a sunny day. On hot days, keep plenty of fluids at hand and drink regularly to prevent dehydration. Cycle at a sensible rate to avoid overheating. Avoid cycling outdoors on days with elevated air pollution levels; you may exercise indoors for a change. > Do not drink alcohol before or during cycling. Avoid cycling with an empty or full stomach. > Warm up and stretch your muscles and joints before embarking on a hard ride, or at least take it easy in the initial stages. > Check with a doctor before taking up challenging or competitive cycling if you have any health concerns or existing medical problems. > Stop cycling if you feel unwell and seek medical advice if indicated. Of note, children under the age of 11 unaccompanied by an adult are not allowed to ride a bicycle on the road. Even in the company of parents or carers, children should only ride on cycling tracks or in recreation grounds (such as parks, playgrounds and waterfront promenades) for safety purposes. Moreover, parents and carers should get their children a bike that fits them. Do not buy a bike that they can grow into. They should also teach children how to ride properly and safely and the basic cycling rules (including the need for courtesy with other road users) and ask them to wear a helmet all the time while cycling. Parents and carers should act as good role models and follow the road rules as a cyclist themselves. For more details on how to cycle safely in Hong Kong, please refer to the Safe Cycling Guides that was available from the Transport Department s website at _guides/index.html. People interested in cycling activities may also visit the Cycling Information Centre at index.html. It is a one-stop information platform which contains relevant information supplied by various Government departments on recreational and leisure cycling activities, including cycling courses, locations of existing cycling tracks and parking sites. References 1. Bauman AE and Rissel C. Cycling and health: an opportunity for positive change? MJA 2009; 190(7): Rivara F and Sattin RW. Preventing bicycle-related injuries: next steps. Inj Prev 2011; 17(3): Bauman A, Titze S, Rissel C, et al. Changing gears: bicycling as the panacea for physical inactivity? Br J Sports Med 2011; 45(10): Oja P, Titze S, Bauman A, et al. Health benefits of cycling: a systematic review. Scand J Med Sci Sports 2011; 21: Hou L, Ji BT, Blair A, et al. Commuting physical activity and risk of colon cancer in Shanghai, China. Am J Epidemiol 2004; 160 (9): Matthews CE, Jurj AL, Shu XO, et al. Influence of exercise, walking, cycling, and overall nonexercise physical activity on mortality in Chinese women. Am J Epidemiol 2007(2); 165 (12): Raglin JS and Wilson M. State anxiety following 20 minutes of bicycle ergometer exercise at selected intensities. Int J Sports Med 1996; 17(6): Knapen J, Sommerijns E, Vancampfort D, et al. State anxiety and subjective well-being responses to acute bouts of aerobic exercise in patients with depressive and anxiety disorders. Br J Sports Med 2009; 43(10): Wilber CA, Holland GJ, Madison RE, et al. An epidemiological analysis of overuse injuries among recreational cyclists. Int J Sports Med 1995; 16(3): Page 6

7 References (cont u) 10. Clarsen B, Krosshaug T and Bahr R. Overuse injuries in professional road cyclists. Am J Sports Med 2010; 38(12): Leibovitch I and Mor Y. The vicious cycling: bicycling related urogenital disorders. Eur Urol 2005; 47(3): Huang V, Munarriz R and Goldstein I. Bicycle riding and erectile dysfunction: an increase in interest (and concern). J Sex Med 2005; 2(5): Thompson MJ and Rivara FP. Bicycle-related injuries. Am Fam Physician 2001; 63(10): Gilchrist J, Thomas KE, Xu L, et al. Nonfatal traumatic brain injuries related to sports and recreation activities among persons aged <19 years Untied States, MMWR 2011; 60(39): Henley G and Harrison J. Injury Research and Statistics Series Number 56: Trends in serious injury data due to land transport accidents, Australia to Canberra; Australian Institute of Health and Welfare; Statistical Release - Reported Road Casualties in Great Britain: Main Results United Kingdom: Department of Transport; Knowles J, Adams S, Cuerden R, et al. Collisions involving pedal cyclists on Britain s roads: establishing the causes. Published Project Report PPR 445. United Kingdom: Transport Research Laboratory; Road Safety: Mortality, distribution of road traffic deaths by road users. Geneva: Global Health Observatory Data Repository; World Health Organization. 19. Weichenthal S, Kulka R, Dubeau A, et al. Traffic-related air pollution and acute changes in heart rate variability and respiratory function in urban cyclists. Environ Health Perspect 2011; 119(10): Cycling Study Final Report Hong Kong SAR: Transport Department. 21. Road Traffic Accident Statistics, Hong Kong SAR: Road Safety and Standards Division, Transport Department. 22. Mortality Statistics, Hong Kong SAR: Department of Health and Census and Statistics Department. 23. Yeung JHH, Leung CSM, Poon WS, et al. Bicycle related injuries presenting to a trauma centre in Hong Kong. Injury 2009; 40(5): Sze NN, Tsui KL, Wong SC, et al. Bicycle-related crashes in Hong Kong: is it possible to reduce mortality and severe injury in the metropolitan area? HK J Emerg Med 2011; 18(3): Major Cyclist Contributory Factor in Traffic Accidents. Hong Kong SAR: Road Safety Council. 26. Thompson DC, Rivara F and Thompson R. Wearing a helmet dramatically reduces the risk of head and facial injuries for bicyclists involved in a crash, even if it involves a motor vehicle. Cochrane Summaries published online: January 21, News Bites A study found that the health and other benefits associated with cycling in an urban environment outweigh the potential risks of road traffic accidents or exposure to air pollution. The study constructed a scenario of people aged shifting from cars to bicycles for short trips of km each day in the Netherlands, and estimated the impact of this shift on all-cause mortality, taking into consideration the health effects of air pollution, traffic accidents, and physical activity obtained from the literature. Results showed that there was a substantial net gain in beneficial effects for the people who shifted from cars to bicycles for short trips a gain in life expectancy of 3-14 months as a result of increased physical activity, set against a loss of days owing to more exposure to air pollution and a loss of 5-9 days due to increased road traffic accidents involving cyclists. For the society as a whole, the gain in benefits were even greater because of a modest reduction in air pollution and greenhouse gas emissions as well as fewer traffic accidents overall. The study concluded that the health benefits of cycling outweigh its potential risks because the health of individual cyclists will improve when they drive less and exercise more. The accompanying decrease in exhaust emissions will also benefit the entire society. [Source: De Hartog JJ, Boogaard H, Nijland H, et al. Do the health benefits of cycling outweigh the risks? Environ Health Perspect 2010; 118(8): ] Page 7

8 Data Brief A local survey showed that a substantial proportion of cyclists did not wear a helmet while cycling, and some of them rode with headphones. The survey was conducted in April 2012 and telephone-interviewed over randomly selected community-dwelling people aged who were asked, among others, a few questions on their cycling behaviour. Of the 589 (28.9%) respondents who reported they rode a bike (excluding stationary bike) in the 12 months before the survey, 88.7% claimed that they had never put on a helmet while cycling; 12.7% rode with headphones listening to the radio, music or answering phone calls at least some of the time. To reduce the risk of head and facial injuries in the event of a crash, cyclists should wear a helmet while cycling at all times. Besides, cyclists should not wear headphones while cycling, because riding with headphones compromises their awareness of approaching cars and other warnings like shouting pedestrians. Frequency of wearing a helmet and headphones during cycling in the 12 months before enumeration Wearing a helmet during cycling All of the time 6.5% Most of the time 1.6% Some of the time 3.3% None of the time 88.7% Wearing headphones during cycling All of the time 2.4% Most of the time 2.4% Some of the time 7.9% None of the time 87.3% Proportion Base: 589 respondents who reported they rode a bike in the 12 months before enumeration. Note: Percentages may not add up to 100% due to rounding. Source: Behavioural Risk Factor Survey, April 2012 (provisional). Editor-in-Chief Dr TH Leung Members Dr Winnie Au Dr KH Kung Dr Regina Ching Mr YH Lee Dr Jacqueline Choi Dr Lilian Wan Dr Alex Fu Dr Francisco Wong Non-Communicable Diseases (NCD) WATCH is dedicated to promote public s awareness of and disseminate health information about non-communicable diseases and related issues, and the importance of their prevention and control. It is also an indication of our commitments in responsive risk communication and to address the growing non-communicable disease threats to the health of our community. The Editorial Board welcomes your views and comments. Please send all comments and/or questions to so_dp3@dh.gov.hk. Page 8